Embracing LOAC Pluralism


| Jan 7, 2022

LOAC Pluralism

​Although the prospect of war remains, the end of two decades of active hostilities affords the United States and its partners the breathing room to rethink their approaches to developing and interpreting the law of armed conflict (LOAC). In my estimation, careful reflection will lead to the conclusion that States, especially those likely to find themselves on tomorrow’s battlefields, must become more active, indeed proactive, in the field. They must embrace LOAC “pluralism,” a subject about which Professor Sean Watts, Co-Director of the Lieber Institute, and I have written in International Law Studies (although these musings are mine alone).

The development and interpretation of LOAC in the 19th and 20th Centuries is a story of pluralism, in which States and non-State actors such as the International Committee of the Red Cross (ICRC) and academics have played complementary roles. This is because LOAC is the product of two sometimes competing values—the need to effectively use force to defend acceptable interests and the desire to limit warfare’s violence to the extent feasible, if only to protect States’ own armed forces and civilian populations. These military and humanitarian considerations operate synergistically to produce a balanced body of law that vindicates both values. Thus, for instance, the rule of proportionality allows an attack in the face of certainty that innocents will be killed, but only if those expected losses are not excessive relative to the “concrete and direct military advantage” the attacker anticipates gaining. Similarly, even when an attack is against a military objective and complies with the rule of proportionality, an attacker must take “precautions in attack” to minimize civilian harm, such as selecting a tactic or weapons system that is least likely to cause harm to civilians and civilian objects, at least so long as military advantage is not sacrificed.

Unfortunately, key States, including the United States, appear hesitant to set forth their views on how LOAC should develop and, more importantly, be interpreted. In particular, they have remained relatively silent in the face of major efforts by the ICRC and academia to restate customary LOAC (as in the ICRC’s Customary International Humanitarian Law study), to comment on how LOAC has developed (as in the ICRC’s Commentaries project), or to apply existing law to new warfare phenomenon (as with the Tallinn and HPCR Air and Missile Warfare Manuals). States tend to limit themselves to criticizing the projects in a general sense, for example, by citing flaws in methodology, disputing isolated issues, or claiming that such efforts intrude upon the near-exclusive province of States.

When this occurs, the balance of military and humanitarian interests is thrown askew. The dynamic that gives LOAC its resiliency and broad credibility is the “give and take” between military and humanitarian considerations. Should participants who tend towards one side of that balancing opt out, the competing interest will wield disproportionate influence.

Consider the ICRC’s Interpretive Guidance on the Notion of Direct Participation in Hostilities. Although a sophisticated product that is a significant contribution to the field (I participated in the project), in my estimation, it proffers several standards crafted out of whole cloth that are simply unworkable on battlefields, such as the so-called “continuous combat function.” Nevertheless, in the absence of overt pushback by States (they left the heavy-lifting to individuals—see here), it has taken on a life of its own. Indeed, CCF has appeared in, or at least influenced, actual rules of engagement. I have even heard U.S. judge advocates cite the purported criterion when discussing which members of an organized armed group may be attacked (the correct answer is “all of them,” bar medical and religious personnel or those who are hors de combat).

I do not want to overstate the problem; States are active in LOAC efforts. For instance, the Tallinn Manual 2.0 Hague Process brought 50 States to the table to offer views on the draft manual, although most remained silent following its publication. States also participate in UN processes examining lethal autonomous weapons systems and cyber, although their public pronouncements on the subjects have lacked granularity. And the promulgation of military manuals, such as the longstanding Navy/Marine Corps/Coast Guard Commander’s Handbook on the Law of Naval Operations, the voluminous DoD Law of War Manual, and the more recent Army/Marine Corps Commander’s Handbook on the Law of Land Warfare are influential contributions to the development and interpretation of LOAC.

But when States have tried to ignore, or express general dissatisfaction with, the work of the non-State community, that approach has hobbled the baked-in pluralistic dynamic that is meant to maintain the military–humanitarian considerations balance that infuses LOAC. Criticism of the work of non-State actors that is unaccompanied by explanation and alternatives has proved relatively ineffective time and again. States need to get into the game fully; LOAC will benefit if they do.

This brings me to my final point. If States are to get into the game, they must enhance their ability to do so effectively. As a graybeard in the field who has worked closely over four decades with judge advocates after retiring as one, I am concerned that our community still lacks the expertise it needs to engage meaningfully in the pluralistic process. The truth is that there are few real LOAC experts in uniform, including in the United States armed forces. In large part, this is attributable to personnel systems that value scope of legal competency (generalists) over depth of expertise (specialists). They tend to develop the diverse professional background necessary to serve as senior judge advocates over the capacity to operate in the LOAC ecosystem.

But this is counterintuitive and counterproductive. Job number one of any armed force is to fight effectively. Thus, the most important legal advice judge advocates can provide is that which is most directly related to combat operations.

My concern is not mitigated much by the fact that the United States and its allies have true experts, such as the U.S. Army’s Law of War advisers. The late Hays Parks, for instance, was a scholar-practitioner renowned internationally for his expertise in the field. These individuals deal effectively with the non-State community and engage meaningfully in inter-State LOAC discussions. But as I explain in a forthcoming International Review of the Red Cross piece, “normative architecture” has to be distinguished from “applied IHL.” The former refers to LOAC’s formal principles and rules, whereas the latter denotes how those rules are applied on the battlefield. The two operate synergistically in the development and interpretation of LOAC. What happens on the battlefield influences our understanding of how LOAC must be interpreted and applied.

Thus, the work of junior and mid-level deployed legal advisers is an essential element of the process by which LOAC develops and is interpreted. But in much the same way that non-military participants in the pluralistic process, especially academics, skew the military and humanitarian considerations balance if they lack an understanding of military operations, so too do military legal advisers who lack a deep grasp of the normative architecture. The paradigmatic example is the too common belief that self-defense is a LOAC notion; it is not. Simply put, competency is not always an adequate substitute for expertise.

Fortunately, States are making progress in addressing the situation. For example, establishing the Lieber Institute at West Point to operate alongside the Naval War College’s Stockton Center was a significant step forward. So too are the global activities of the International Society for Military Law and the Law of War. And some nations are investing heavily in formal LOAC education. The British Army and the Royal Air Force, for example, are growing in-house PhDs.

The IDF’s International Law Department is a model other nations would do well to emulate. The IDF develops LOAC experts early in their careers and allows them to focus on the subject throughout it, albeit in a variety of positions. Until we adopt the approach of the IDF, we are doomed to be out-lawyered by those who have dedicated themselves to the field full time, like the ICRC’s impressive thematic lawyers.

Do not draw the wrong conclusion. I am not suggesting that an adversarial relationship exists, or even should exist, between the governmental (especially military) legal community and non-State participants like academics and ICRC lawyers. On the contrary, my point is the opposite, for most members of the LOAC community share the goal of achieving balanced law. We just bring different assets to that joint undertaking.

Ultimately, getting the law right means that the process of developing and interpreting LOAC must be inclusive. All those who participate must understand that both military and humanitarian values underpin this body of law. And they should equally understand that both the “normative architecture” and “applied IHL” matter. Accordingly, States should recommit themselves to becoming fully engaged participants in what is necessarily a pluralistic endeavor. Doing so not only means participating actively as States but also growing highly qualified military LOAC experts who can leverage operational understanding in the common pursuit of law that reflects both military and humanitarian considerations. It is time to embrace LOAC pluralism.


Michael N. Schmitt is the G. Norman Lieber Distinguished Scholar at the United States Military Academy. He is also Professor of Public International Law at the University of Reading, Strauss Center Distinguished Scholar and Visiting Professor of Law at the University of Texas, and Professor Emeritus at the United States Naval War College.